neon library integration part I

[Christian Kellner <gicmo xatom net>]

Hi!

So this is the fist patch[1] of the neon integration plan. I decided to
put the neon lib in $srcdir/neon (or should we use libneon?)

(1) It adds the macros necessary to initialize the neon bundled build to
acinclude.m4 (there are to sections: the first one is the section with
own macros and macros I made changes to, the second one is the one I
just copy and pasted untouched).
(2) It also adds the necessary macro to configure.in (and removed the
unused MODULES_XML stuff)
(3) It adds the necessary SUBDIR entry in the toplevel Makefile.am

I didn't include the whole neon library for sure :)

The ChangeLog entry is a bit ugly and could be redone ;)

I'd suggest to add the complete neon src dir first and then adding the
patches necessary to replace the io layer to keep track of the changes.

Cu!
Christian

[1] http://www.fmi.uni-passau.de/~kellnerc/neon_integration_part_1.patch